Muller and his teammates managed a 2-1 victory in Vienna in October, and he said that the return leg will be similarly tricky.
"The last game in Vienna was really uncomfortable," Muller told Bundesliga.com.
"They have some dangerous players in attack. On a good day they can make life really difficult. David Alaba will probably be in midfield. He has a really good long shot. I'll send him a message in the morning if we win."
Germany currently sit top of World Cup qualifying Group C with 16 points from 18.